1. Field
Embodiments of the invention relate to the field of microprocessors, and more specifically, to frequency management.
2. Background
Advances in microprocessor technology have provided users with high level of performance flexibility. For example, mobile processors offer users two performance modes: Maximum Performance mode and Battery Optimized mode. Maximum Performance mode takes advantage of the additional power provided by an alternating current (AC) power source to provide a new level of mobile personal computer (PC) performance, while Battery Optimized mode provides optimal performance while running on battery. In Maximum Performance mode, the processor delivers highest performance at the expense of high power consumption. In Battery Optimized mode, the processor provides lower performance but consumes much less power.
Recently, demands for high performance have accelerated development of very fast processors at more than 1 GHz operating frequency. Thermal throttling or monitoring and other performance operations feature power management by changing the frequency at which the processor operates. In existing circuits, frequency switching between performance states requires the processor to stop execution during frequency transition. This transitioning from one mode to another may lead to many undesirable effects such as excessive bus master and software latency, end-user visible artifacts (e.g., audio drop-out, video frame loss), and component stress.